Feeling forgetful? It's not always Alzheimer's

Though Alzheimer's disease is by far the most common type of dementia, it's not the only possible culprit if you notice a loved one starting to act a little odd with age.

Alzheimer's is caused by plaques in the brain that act as “roadblocks,” keeping the brain cells from communicating. “Tangles,” or dying neurons, also form in the brain when the tubes that allow nutrients to move around the brain cells collapse.

Alzheimer's accounts for 50-70 percent of cases of dementia, according to the Alzheimer's Association. Determining the exact number of cases is difficult because many types of dementia cause similar symptoms, and some patients may be incorrectly diagnosed with the wrong kind of dementia or with an unrelated condition before the source of their symptoms is found.

Vascular dementia is believed to be the second most common type of dementia, according to the Alzheimer's Association. It occurs when one or more clots block the flow of blood and oxygen to the brain, and can be caused by one major stroke or a series of small strokes, which cause slowly escalating brain damage.

Common symptoms of vascular dementia are memory problems, difficulty paying attention and confusion. It is most common in people who have a history of heart attacks or risk factors for heart problems, such as high blood pressure, high cholesterol or diabetes. Some people develop both Alzheimer's and vascular dementia.

CAUSES OF DEMENTIA

• Alzheimer's disease, 50-70 percent

• Vascular dementia, 10-15 percent

• Lewy body dementia, 10-20 percent

• Frontotemporal dementia, 5-10 percent

• Parkinson's dementia, 3-4 percent

Source: Dr. Bruno Giordani

Lewy body dementia, though less well known, may be as common as vascular dementia. It is caused by buildup of protein deposits, known as “Lewy bodies,” in the cells of the brain.

Symptoms of Lewy body dementia include problems with memory and judgment, confusion, visual hallucinations, daytime drowsiness and physical symptoms like stiffness, a shuffling walk, shakiness and trouble with balance. In some cases, people sleepwalk and act out their dreams because their brains no longer block their bodies' movements during sleep.

Lewy bodies also appear in patients with Parkinson's disease, which can also cause dementia in its later stages, and causes many of the same physical symptoms as Lewy body dementia.

Other causes of dementia are more rare. Frontotemporal dementia is expected to cause 5-10 percent of dementia cases, and typically affects younger people than most other dementias. It affects the front and sides of the brain, but its causes are unclear, according to the Alzheimer's Association.

It typically affects judgment and social skills, causing those to have it to make bad decisions or make inappropriate remarks that are out of character. Some also develop an unusually large appetite and gain weight.

Very rarely, dementia can be caused by an increase in the pressure of brain fluid, thiamine deficiency related to alcoholism, the genetic disorder Huntington's disease and Creutzfeldt-Jakob disease, which can be caused by mutations or exposure to the brain or spinal fluid of someone who had the disease.